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 A093011 Primes of the form 10*R_k + 3, where R_k is the repunit (A002275) of length k. 3
 3, 13, 113, 11113, 111111113, 11111111113, 111111111111111111111113, 111111111111111111111111111111111111111111111111111111111111111111111111111111111113 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes of the form 2 + (10^k - 1)/9, k > 0. - Vincenzo Librandi, Dec 13 2011 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..9 Makoto Kamada, Prime numbers of the form 11...113. Index entries for primes involving repunits MATHEMATICA Select[Table[(((10^n-1)/ 9)+2), {n, 1, 900}], PrimeQ] (* Vincenzo Librandi, Dec 13 2011 *) PROG (Magma) [a: n in [1..100] | IsPrime(a) where a is ((10^n-1) div 9)+2 ]; // Vincenzo Librandi, Dec 13 2011 CROSSREFS Cf. A056654 (corresponding k). Sequence in context: A053583 A077713 A119723 * A262147 A364327 A057865 Adjacent sequences: A093008 A093009 A093010 * A093012 A093013 A093014 KEYWORD nonn AUTHOR Rick L. Shepherd, Mar 14 2004 STATUS approved

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Last modified May 27 00:30 EDT 2024. Contains 372847 sequences. (Running on oeis4.)